Tool.



G. F. RIESENWEBER.

V TOOL. APPLICATION IILIBD HAY26, 1904.

Patented 001;.26, 1909.-

2 SHEETS-SHEET 1.

Inventor:

Witnesses:

' 7 w dzg G. F. RIESENWEBER.

. a, 1904. I 938 339, Patented 0011.26, 1909. 9 z SHEETS-SHEET 2.

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CARL F. RIESENWEIBER, OF ST. LOUIS, MISSOURI.

TOOL.

Specification of Letters Patent.

Patented Oct. 26, 1909.

Application filed May 26, 1904. Serial No. 209,875.

To all whom it may concern:

Be it known that I, CARL F. RIESENWEBER, a citizen of the United States,and a resident of the city of St. Louis and State of Missouri, haveinvented a new and useful Improvement in Tools, of which the followingis a specification.

My invention relates to taps for threading holes in separated plates,as, for example, stay-bolt holes in locomotive boilers.

It has for its principal objects to facilitate the reaming and threadingof holes; to accurately thread alined holes in separated plates so thatthe two threads shall lie in the same helicoid surface; to shortenstaybolt taps; to reduce the number of taps required to thread all thestay-bolt holes in a locomotive boiler; and other objects hereinaftermore fully appearing.

My invention consists in the parts and in the arrangements andcombinations of parts hereinafter described and claimed.

Inthe accompanying drawings forming a part of this specification andwherein like symbols refer to like parts wherever they occur, Figure 1is a view of a compound stay-bolt tap comprising two taps on a threadedspindle, one of said taps being shown in section; Fig. 2 is a View of acompound stay-bolt tap, one of the taps being integral with the threadedspindle; Fig. 3 is a section in the plane of the line 3 3 of Fig. 2;Figs. 4 and 5 are fragmentary sectional views in the planes of the lines4: 4 and 5 5 of Fig. 3 respectively; Figs. 6 and 7 are fragmentarysectional views of a modification corresponding to Figs. 4. and 5respectively; Fig. 8 is a vertical sectional view'through the fire-boxportion of a locomotive boiler; Fig. 9 is a view of a small part of afire-box sheet showing the manner in which these sheets crack inservice; Fig. 10 is a view'of a reamer constructed according to myinvention.

In many places it is desirable to connect two separated plates or sheetsby bolts having screw threaded engagement with both. The construction oflocomotive boilers is a familiar example of this, the plates of thewater legs and the crown sheet and outer sheet over the fire-box beingconnected by stay-bolts. To properly effect this connection it isnecessary for the-holes to be perfectly alined and parallel with thedirection of the stay-bolt and for the threads of alined holes to lie inthe same helicoid surfaces. It is the common practice to prepare thestaybolt holes by means of a tool comprising a reamer, a tap, and ashank. As the reamer must be long enough to aline the tool, and the tapmust be long enough to start the thread in the inner or second platebefore being disengaged from the thread in the outer or first plate, andthe shank must be long enough to make it possible to finish the inner orsecond thread, this tool is necessarily about three times as long as thedistance between the plates. These tools must be hardened, which, onaccount of their length, is very difficult, if not impossible, to dowithouta change in the lead of the thread and without warping. Thesechanges in shape are so great as to render a large portion of the toolsmade useless and a considerable number of imperfect ones are put intouse. The said change in lead is very objection able for if a stay-boltis forced into place and one of the threads does not mesh with thethread in the corresponding plate, a boiler explosion is likely to bethe result. Such a tool long enough to thread the holes for thestay-bolts in one part of a boiler cannot be used to thread the holesfor the staybolts in another part, because it interferes with someportion of the boiler. Consequently a large number must be provided.This tool is expensive, is a source of loss and vexation to the boilermaker, and is a source of danger to the user of the boilers. Myinvention is designed to overcome these objections.

My improved tapping tool comprises a threaded spindle having a tap ortaps mounted thereon. The spindle 1 is provided with a thread of anydesired shape and pitch which may continue from end to end of thespindle or may be interrupted at the middle portion of the spindle. Thelatter case is illustrated. The threads on the opposite ends lie in thesame helicoid surfaces, each being a continuation of the other. spindleis preferably made of annealed carbon tool steel and is not hardened forit is not used as a cutter at all. Distortion of the threads in thehardening process is thus avoided, and the finished spindle is true. Thespindle is provided with a polygonal enlargement 2 by means of which itmay be held or turned in the taps in case of sticking. A spindle screwthreaded throughout its This i llC entire length might be provided withkerfs in the ends for a screw driver or with check nuts.

Upon the spindle hollow taps 3, 4 are screwed. These taps are made byplacing them on the spindle and threading them in place. same pitch andcorrespond exactly with the threads on the spindle. Consequently thethreads on one tap have the same pitch and correspond to the threads onthe other tap. At their outer ends the taps 3, 4 are provided withpolygonalheads 5, 6 respectively, to provide for the turning of the tapsby means of a wrench. Notches 7, S are cut in the ends of the taps, saidnotches extending to the threaded hole through the taps. The walls ofthe notches act as scrapers to clean out the threads of the spindle.Similar notches 9, 10 are cut in the ends of the spindle and their wallsact as scrapers to clean the threads in the taps. The taps arepreferably made of alloy tool steel because of the great superiority inits cutting qualities over carbon tool steel. They are hardened withgreatly reduced distortion of the threads because they are so short,each tap being required to be only long enough to thread a hole in asingle plate.

In use one of the tapes is removed from the spindle, and the latter withone tap in place is passed through the two holes; after which the firsttap is replaced on the spindle. The taps are then both in position tooperate on their respective plates 11, 12 and may be simultaneouslyoperated, one man working on the interior and another working on theexterior of the boiler. Each tap holds the other to its work and thespindle serves as a positive feed for them insuring true threads andalinement. The holes having been threaded the taps are removed andanother pair of holes may be threaded in like manner. One spindle can beused upon a large number of pairs of holes as it is necessary for it toextend beyond the inner plate only far enough to receive the tap, theother end of the spindle projecting outside the boiler. For this reasonalso my improved tap can be used to thread holes upon which the oldstay-bolt tap could not be used at all. Spindles are made of variousconvenient lengths and of a. standard diameter and any tap will fit anyspindle of a set.

Ordinarily, the inner or advance ends of the taps form reamers 13, 14L,which ream out the holes in advance of the threading cutters. But whenmuch metal is to be removed, it is desirable to use a reamer. A suitabletool is illustrated in Fig. 10. It comprises a spindle 15 like thespindle in the tap. Upon it are placed reamers 16, 17 screw threadsfitting the threads on the spindle. tap, the spindle serving to insurealinement The threads on the taps have the provided with This reamingtool is used like the 7 of the holes and as a positive feeding means forthe reamers.

It is sometimes desirable to make one of the taps rigid upon or integralwith the spindle. A tool of this type is shown in Fig. 2. A spindle 18is provided with an integral tap 19 of any desired diameter at one end.The spindle 18 is provided any desired shape and pitch and the tap 19 msthreads of the same pitch as and corresponding to the threads on thespindle. A hollow movable tap 20 is mounted on the spindle similarly tothe mounting of the taps 3 a on the spindle 1. The spindle 18 and tap 19integral therewith are made of alloy tool steel. The tap is hardened butthe hardening extends only to the spindle, leaving the latter unhardenedand avoiding the detrimental efiects upon it of the hardening process.The tap 22 is made of alloy tool steel and hardened. The end of thespindle 18 is provided with a polygonal portion 21 by means of which itmay be turned. The tap 20 is provided with a polygonal portion 22 bymeans of which it may be turned. This form of tool is especially usefulin patching jobs when the work is done upon the boiler in place on itsframe and it is diflicult or impossible to work on one side.

It is common for cracks 23 extending radially from the stay-bolts toappear in the inner fire-box sheet 24, in that portion of the sheet incontact with the hottest part of the fire, as illustrated in Fig. 9. Itis proposed to mend such places by drilling or chipping a holeconcentric with the staybolt and extending beyond the end of the crack,as indicated by the dotted circle 25. A special stay-bolt 26 is providedhaving a threaded portion to fit the hole in the outer plate and anenlarged and threaded portion 27 to fit the large hole in the innerplate. My improved tool is adapted for threading these holes as a tap ofa proper size to thread the smaller hole can be put on one end of thespindle and a tap of a proper size to thread the larger hole can be puton the opposite end of the spindle. If the patch staybolt is to beinserted in a part so'located that working from the exterior isinconvenient, as when the frame 28 or some other part is in the way themodification shown in Fig. 2 should be used.

with threads of iii The taps may be provided with ordinary rib 32 issimilar to the rib 30. The invention is shown in these figures appliedto cutting teeth of a bottoming tap, the shape of ordinary cutting teethbeing indicated by the dotted lines. Adjacent faces of each pair ofteeth, as 38 and 34, are provided with angular cutting edges, thecutting edges upon the opposite faces being shortened, as if the oldform of tooth were truncated at an angle to the axis of the tap. Theteeth upon the succeeding rib of the tap are similarly shaped but are solocated that the tooth 35 immediately succeeding the tooth 33 and thetooth 36 immediately succeeding the tooth 34c are truncated upon thesides opposite to the truncation of the teeth 33 and 34-. Thus eachtooth is required to cut away only a portion of the metal removed by theold form of tooth. At ,last, teeth of triangular shape follow and cutaway the small amount of metal remaining in the bottom of the thread. Bythis expedient the force necessary to turn the tap is much reduced. Allforms of tap cutting teeth, whether taper taps, plug taps, or bottomingtaps may be improved in this way. The alternate portions of succeedingteeth of the old shape are cut away.

A modification is illustrated in Figs. 6 and 7. In the ordinary cuttingteeth both faces of a tooth are provided with cutting edges. In thismodification the teeth are cut away on one side so as to provide cuttingedges on one side only. Alternate faces of succeeding teeth are providedwith cutting edges, one tooth cutting one side of the thread and thesucceeding tooth cutting the opposite thread.

Obviously this device is capable of modification within the scope of myinvention and therefore I do not wish to be limited to the specificconstruction shown and described. F or example, in the modificationshown in Fig. 2, the spindle 18 may be made of carbon tool steel and thetap 19 may be made of a separate piece of alloy tool steel and rigidlysecured to the spindle.

That I claim as my invention and desire to secure by Letters Patent is:

1. A tool comprising a threaded spindle, a tap rigid with said spindle,and a hollow internally threaded tap working on said spindle and havinga diameter greater than the diameter of said first mentioned tap, saidtaps being arranged to work in the same direction and cut threads havinga pitch corresponding to the pitch of the threads on said spindle.

2. A tool comprising a threadedspindle, a tap rigidly attached to saidspindle, and a hollow internally threaded tap working on said spindle,said taps being arranged to work in the same direction.

In testimony whereof I have hereunto signed my name in the presence oftwo subscribing witnesses this twentieth day of May, 1904, at St. Louis,Mo.

CARL F. RIESENWEBER.

Witnesses ARTHUR HAERTING, FELIX E. GoERLIoH.

